Primers backing out!!

[mudbug]

I have a Savage Model 112 that I just had rebarrelled to 6mm-284. I took Lapua 6.5-284 brass ran it thru the 6-284 Redding FL die and loaded 53 grains of Retumbo with 105gr Bergers to a length of 2.370 at the ogive. At the range the primers backed out on the first firing.

Anyone have any thoughts as to why?

The resized brass measures 1.797 before firing and 1.803-1.805 after firing-used Hornady Headspace gauge to measure. I measured my headspace gauges I took to the gunsmith for him to install the barrell and the go-gauge measures 1.801, the no-go gauge measures 1.805. The shoulder moved forward .006-.009 and the necks are visible shorter.

I don't think this is a headspace issue, I think that maybe I need to turn the necks. A bullet will not slide thru the neck of an unsized case.

What do ya'll think?

My barrel is a Shilen 8 twist stainless select and I have not seen any markings to say it is a tight neck chamber.

 

[jimbires]

the primer backing out could be caused by to light of a load , not enough pressure . I don't load or shoot a 6x284, but retumbo sounds slow for this . I'd guess you want to be in the varget , 4831 , 4350 range of powder speed .

 

[mudbug]

I used Retumbo because in the Hodgdon reloading manual it lists the starting load of 53gr with a 107 Sierra HPBT.

I may try some H4831 and see how it does.

Thanks for the reply

 

[jimbires]

I just did a quick check on my quick load . 6x284 with a 105 berger vld using 53.0 grains of retumbo is roughly 41400 psi and 98% case fill .
retumbo 58.0 grain is 107.9 % fill and 56547 psi that is near max load.
retumbo 59.1 grains is 109.9 % fill and 60641 PSI this is a DANGEROUS load .


I think you have low pressure problems . Jim

 

[Loner]

Check your chamber for being a bit rough. Lightly polish it if it is. Also you can shoot
those light loads with some sizing wax on them to fire form them if your brass is not
stretching rearward. At least that is what I think you are say is the problem.

 

[mudbug]

I even shot 56.5 gr of retumbo and had the same thing happen. The primers were flat on both loads. I'm thinking that since the cases had to stretch so much forward that may have caused the primers to back out, not sure though. I'm going to reload a couple of the once fired cases and see if it happens again. I will try some different powder also, I've got load data from walt berger for the 6x284 and will try some H4831sc.

If anyone has a 6x284 please chime in and give me your opinion and favorite load if you don't mind.

Thanks,

Mudbug

 

[bigngreen]

I would jam the bullet into the lands and fire form them so your blowing it out to the shoulder not back to the bolt face. Sounds like your brass isn't getting the traction on the chamber and slamming back after pushing the primer out a few thou.

 

[cva54]

I am having the same prob with a 721 30.06. I am new at this! Powder is IMR4350 52.3 gr WLR primers pushing a 150 gr FMJ/BT. primer is flat and pushed out .003 had them countersunk that far. Shouldnt be head spacing I partial resized twiced fired brass. Think I got a detonation problem or the powder is slow burnning. I found this in a old P.O. ACKLEY book copyright 1962 10th print 1977, "Here is a laboratory test in .30/06, using I.M.R 4350, 170 grain Hornaday bullet, Winchester Case, Winchester Primer. Reloaders have been warned not to use this load. It is a good, safe, dependable load.

Grains 4350 Pressure
55 gr. 38,600
55.5gr. 41,800​

Mr. Hodgdon has complet pressure equipment as does the author, and like Mr. Hodgdon, the author had not yet been able to produce detonation experimentally. However, the author fully expects to prove the theory in the laboratory in the not too distant future"(107). Can some one out there make any sence out of this. If so let me in on it​